Electrical Information
Vehicle
Page 3-2
Crestline
Manual
1/30/2006
Coach
Charging/Electrical Systems
Thereare fivecomponents common to theelectrical chargingcircuitsof eachmodel of ambulancebuilt
byCrestline.
These items are:
1)O.E.M factorybattery
2)Dedicatedconversionbattery
3)Highoutput alternator
4)Battery isolator
5)Fast idle throttle control
On all Ford chassis, onlydiesel engines are approved for ambulance usage. Thus, theFord ambulance
preparationpackage includes dual factorybatteries, anddual factory installed110 amp alternators. On
2004 andnewer Ford chassis’, bothOEMbatteries comemounted to thepassenger side frame rail and
Crestline installs them in the step well of the conversion frame. The ambulance battery and battery
isolator are suppliedand installedbyCrestline.
FactoryBatterySystem
The O.E.M. factory battery system provides power to the factory circuits and accessories only. This
includes the headlights, instrument cluster, signal lamps, engine electrical circuits, etc. Since this
battery is the primary power source for starting the engine, it is essential to connect the voltage
regulator to this battery. Thus the regulator ensures that the alternator supplies enough current to
maintain a fully charged factory battery for ease of starting. This is the case regardless ofwhether the
alternator is installedby thechassismanufacturer or byCrestline.
Toensure satisfactorybatteryperformance, battery terminal cleanliness is essential.
DedicatedConversionBattery
The ambulance battery is typically installed in an exterior compartment on the left hand side of a
modular ambulance body. This battery provides power to all conversion circuits. This includes all
warning lights, sirens, patient compartment lights, heater andA/C, etc. Since the current drain due to
theambulance load isoftenprolonged, theambulancebattery is aDeepCycleR.V typematched to this
type of load. The alternator provides charging current to this battery through the battery isolator; the
voltage is regulated to the same level as that on the factorybattery.
HighOutputAlternator
The Ford ambulance prep package comes complete with two 110-ampOEM alternators. These are
necessary to supply the large current demand of a modern ambulance. The alternator must have
enough capacity at highoperating temperatures tomeet or exceed theentireelectrical load imposedby
anemergency response situation.
To ensure satisfactory alternator operation, it is essential to check the alternator belts frequently for
correct tension.
